The present invention relates to a milk-based powder for pets. Particularly, the present invention is directed to a pet milk composition that may be reconstituted to provide a milk-based nutritional composition for pets, especially for young pets.
Many pet owner""s, especially owners of young pets, feed cow""s milk or cow""s milk based compositions to their pets since cow""s milk is an excellent source of nutrition. Further, in cases where very young pets are unable to obtain milk from their mothers, cow""s milk or compositions based upon cow""s milk may be the only source of nutrition for the young animal.
Unfortunately, the feeding of cow""s milk to pet mammals may result in gastrointestinal intolerance. This manifests itself in a variety of intestinal symptoms which include bloating, distension, cramps, flatulence, lower fecal consistency and, in severe cases, diarrhea. Lower fecal consistency and diarrhea are particularly well known symptoms. (Mundt, H. C. and Meyer, H.; 1989, Waltham Symposium 7: Nutrition of the Dog and Cat, Cambridge University Press, pages 267-274). The cause of the gastrointestinal intolerance is attributed to the lactose in cow""s milk.
Removal of lactose from cow""s milk for human applications is well known. This is usually done by micro- or ultra-filtration or enzymatic treatment, or both, of liquid milk or whey solutions. Further milk or whey powders which are low in lactose, or lactose-free, are commercially available and may be fed to pets, but these powders are generally too expensive for commercial use in pet products. For pets, a possible solution to the problem is described in EP 0259713, where the lactose in the composition is reduced by reducing the content of milk powder in the composition to below about 60% by weight. In order to make up for the reduction in protein, lactose-reduced or lactose-free milk proteins are then added to the composition. In this way, the lactose content of the composition may be reduced to below about 30% by weight, but this requires the addition of large amounts of lactose-reduced or lactose-free milk proteins which increases the cost.
Mundt and Meyer, supra, suggest that another solution to this problem is to hydrolyze the lactose using enzymes prior to producing the pet milk powder. This is an acceptable solution when milk is freely and inexpensively available in liquid form, but it is not a feasible solution when the milk ingredient is available in powdered form; which is commonly the case.
Thus, there remains a need for a cow""s milk-based powder which may be reconstituted to provide a milk-based nutritional composition, which is relatively simple to prepare and relatively inexpensive.
In one aspect, this invention provides a pet milk powder comprising a cow""s milk powder which contains lactose, and a lactase. It has been surprisingly found that the simple addition of lactase to milk powder is able to avoid or significantly reduce the gastrointestinal problems associated with the consumption of lactose. This is despite the fact that the milk composition produced by reconstituting the milk powder may be consumed immediately after reconstitution; that is before the lactose has had the time to degrade the lactose in the milk powder. Preferably, at least a portion of the lactose in pet milk powder will become hydrolyzed upon reconstitution with solvent. Accordingly, upon reconstituting the pet powder product as a drink, and before its ingestion by the pet, the composition will comprise hydrolyzed and unhydrolyzed lactose. Preferably, 5 to 80% of the lactose is hydrolyzed upon reconstitution with a solvent.
Preferably, the lactase is a xcex2-galactosidase, and more preferably, the xcex2-galactosidase is from micro-organism origin. A xcex2-galactosidase that is active at an acidic pH is particularly preferred.
The milk powder may further comprise one or more of a lipid source, protein source, vitamins, and minerals.
In another aspect of the invention, the milk powder is formulated for cats, the powder comprising a cow""s milk powder which contains lactose, a lactase, taurine, arginine and choline. In yet another aspect of the invention, the milk powder is formulated for dogs, the powder comprising a cow""s milk powder which contains lactose, lactase, and choline.
In a further aspect, the invention provides a method for reducing the symptoms of gastrointestinal intolerance in a mammalian pet after consumption of a nutritional composition based on cow""s milk, the method comprising administering to the pet an effective amount of lactase in combination with the nutritional composition.
Preferred embodiments of the invention are now described by way of example only.
The invention concerns a milk-based powder which may be reconstituted with water or other solvent to provide a nutritional drink for pets comprising hydrolyzed and unhydrolyzed lactose before ingestion.
The milk-based powder contains cow""s milk powder and a lactase. The cow""s milk powder may be any suitable milk powder which is based upon cow""s milk; for example skimmed milk powder and whole milk powder. Further, milk powders produced from standardized milk-based solutions may be used. If desired, the cow""s milk powder may contain additives such as vitamins, minerals, protein, lipids, and the like. The lactose content of the milk powder is not critical to the invention. Of course, if cow""s milk powders having low lactose contents are readily and inexpensively available, they may be advantageously used.
The lactase may be any suitable lactase which is generally recognized as safe. xcex2-galactosidases are preferred; especially xcex2-galactosidases of microbial origin. Since conditions in the gastrointestinal tract are acidic, a lactase which remains active under acidic conditions is preferred. It is also possible to use lactases which are active under neutral or basic conditions. In these cases, however, it may be useful to include an alkali in the milk-based powder which slows the pH drop in the gastrointestinal tract.
An enzyme which is particularly suitable is a xcex2-galactosidase which may be obtained from Amano Enzyme USA Co Ltd of Lombard, Ill., USA. The enzyme is available under the name xe2x80x9cLactase Amanoxe2x80x9d. The enzyme is obtained from Aspergillus oryzae and has an optimum pH of about 4.8 when lactose is the substrate. The enzyme has an activity of more than 50000 units/g at optimum pH. The enzyme is generally recognized as safe and is food grade.
The amount of the lactase to be added will depend upon various factors such as the lactose content of the cow""s milk powder and the activity of the enzyme. The useful amount may be readily determined by a skilled person. Ordinarily, the lactase may be added to provide about 25 UI100 g to about 200 UI/100 g powder; for example about 50 UI/100 g to about 125 UI/100 g powder. The unit, UI, indicates the amount of enzyme which produces 1 micromole of o-Nitrophenol per minute at 30 degree. C. when 3.0 ml of a solution which contains 200 mg of -Nitrophenol-.xcex2galactopyranoside per 100 ml of 0.1 M Mcllvaine buffer, pH 4.5; is added to 1.0 ml of diluted enzyme solution. The reaction is stopped after 10 minutes.
For an enzyme which has an activity of about 50 UI/100 g to about 125 UI/100 g powder, the lactase may comprise about 0.05% to about 0.4% by weight of the milk-based powder; and preferable from about 0.15% to about 0.25% by weight.
If it is desired to make the milk-based powder more nutritionally complete, other nutritional components may be added to the powder. For example, a lipid source may be added to the milk-based powder. Any suitable lipid source may be used; for example vegetable oils such as soybean oil, sunflower oil, safflower oil, corn oil, peanut oil, and rapeseed oil, or animal fats such as milk fats and tallow. In general, the lipid source used will be selected on the basis of nutritional value, cost and palatability considerations.
It is also possible to add further protein and amino acids sources. For example, whey protein powders may be added to the milk-based powder. Similarly, the milk-based powder may be supplemented with free amino acids which are required by the mammal for complete nutrition. For example, for milk-based powder intended for kittens, the powder may be supplemented with taurine or arginine, or both.
The milk-based powder may also contain vitamins and minerals. It is particularly preferred to include a source of calcium; for example dicalcium phosphate.
The milk-based powder may also include a probiotic micro-organism. A probiotic micro-organism is a micro-organism which beneficially affects a host by improving its intestinal microbial balance (Fuller, R; 1989; J. Applied Bacteriology, 66: 365-378). In general, probiotic micro-organisms produce organic acids such as lactic acid and acetic acid which inhibit the growth of pathogenic bacteria. Examples of suitable probiotic micro-organisms include yeasts such as Saccharomyces, Debaromyces, Candida, Pichia and Torulopsis, molds such as Aspergillus, Rhizopus, Mucor, and Penicillium and Torulopsis and bacteria such as the genera Bifidobacterium, Bacteroides, Clostridium, Fusobacterium, Melissococcus, Propionibacterium, Streptococcus, Enterococcus, Lactococcus, Staphylococcus, Peptostrepococcus, Bacillus, Pediococcus, Micrococcus, Leuconostoc, Weissella, Aerococcus, Oenococcus and Lactobacillus. Specific examples of suitable probiotic micro-organisms are: Saccharomyces cereviseae, Bacillus coagulans, Bacillus licheniformis, Bacillus subtilis, Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium longum, Enterococcus faecium, Enterococcus faecalis, Lactobacillus acidophilus, Lactobacillus alimentarius, Lactobacillus casei subsp. casei, Lactobacillus casei Shirota, Lactobacillus curvatus, Lactobacillus delbruckii subsp. lactis, Lactobacillus farciminus, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus reuteri, Lactobacillus rhamnosus (Lactobacillus GG), Lactobacillus sake, Lactococcus lactis, Micrococcus varians, Pediococcus acidilactici, Pediococcus pentosaceus, Pediococcus acidilactici, Pediococcus halophilus, Streptococcus faecalis, Streptococcus thermophilus, Staphylococcus carnosus, and Staphylococcus xylosus. The probiotic micro-organisms are preferably in powdered, dried form; especially in spore form for micro-organisms which form spores. Further, if desired, the probiotic micro-organism may be encapsulated to further increase the probability of survival; for example in a sugar matrix, fat matrix or polysaccharide matrix.
Further, the milk-based powder may also include a source of a fermentable soluble fiber, for example, chicory fibers, inulin, fructooligosaccharides, and the like. Preferably the fermentable soluble fibre selected is a substrate for the probiotic micro-organism selected, or such that the fermentable soluble fibre and probiotic micro-organism form a symbiotic relationship for promoting beneficial effects.
It is of course possible that vitamins, minerals, amino acids and a lipid source may have been used in the preparation of the cow""s milk powder. In this case, less or none of these ingredients need be added.
The milk-based powder may be manufactured by dry mixing the cow""s milk powder, the lactase, and any other ingredients. If a lipid source is added, it is preferably mixed in last. Any suitable mixing apparatus may be used. The milk-based powder is then packed into suitable packages.
The amount of the nutritional composition to be fed to a mammal each day will depend upon factors such as the mammal""s age, the type of mammal, and other sources of nutrition. In general, the nutritional composition may be used in much the same way and in the same amounts as milk is used. For example, for medium and large dogs, up to about 250 ml of the nutritional composition per day may be fed to the dog. For smaller dogs, up to about 125 ml of the nutritional composition per day may be fed to the dog. Similar values may be readily determined for cats and other mammals.